Detecting the presence of water in media which are substantially electrically non-conductive such as grease and oil is a difficult problem, and particularly to the food, the petrochemical and rendering industries. In the rendering industry, a prime source of raw materials is grease and oils produced as by-products by other industries such as the grease produced by restaurants. This grease is often contaminated with water, sometimes intentionally added. It is important to determine how much water is in the grease so that renderer does not pay unnecessarily for a valueless raw material, namely water.
The technique most commonly used by the rendering industry for detecting the presence of water in grease is insertion of a "trier", a hollow sampling tube, into a container of the grease. The trier is withdrawn from the container, bringing with it layers of grease and water. With a trier, continuous layers and sometimes pockets of water can be detected. However, it is very difficult to accurately determine the thickness of water layers and to locate small pockets of water with a trier.
Therefore, there is a need for an easy-to-use, accurate, and inexpensive water-in-grease detector and measuring device. It is important that the device be inexpensive because it is desirable that the apparatus be used as a replacement for the trier on practically every grease collection truck in the nation, which includes thousands of trucks.